Tektronix MTS4EA Elementary Stream Analyzer Training/Tutorials
xx
MTS4EA
ZZZ
Elementary Stream Analyzer
Tutorials
This document applies to software version 6.0.
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Table of Contents
Getting Started ........... . . . . . . . . . . . . . . ..................... . . . . . . . . . . . . . . . ..................... . ........... . . . . . . . . 1
Basic Functions ................................................................................................ 2
How to Begin a Tutorial ............. ................................ ................................ ......... 2
Tutorial 1: H.
Procedure ....................................................................................................... 3
Conclusion...................................................................................................... 9
Tutorial 2: H.263 Compliance and Motion Vectors ........................................................... 10
Procedure ...................................................................................................... 10
Conclusion..................................................................................................... 15
Tutorial 3: M
Procedure ...................................................................................................... 16
Conclusion..................................................................................................... 22
Tutorial 4: MPEG-4 Optimization............. ................................ ................................ .. 23
Procedure ...................................................................................................... 23
Conclusion..................................................................................................... 30
Tutorial 5: M
Procedure ...................................................................................................... 31
Conclusion..................................................................................................... 36
Tutorial 6: MP4 Optimization.................................................................................... 37
Procedure ...................................................................................................... 37
Conclusion..................................................................................................... 41
Tutorial 7:
Procedure ...................................................................................................... 42
Conclusion..................................................................................................... 46
Tutorial 8: H.264/AVC Syntax Error............................................................................ 47
Procedure ...................................................................................................... 47
Conclusion..................................................................................................... 50
Tutorial 9:
Procedure ...................................................................................................... 52
Conclusion..................................................................................................... 63
Tutorial 10: MPEG-2 Compliance..................... .................................. ........................ 64
Procedure ...................................................................................................... 64
Conclusion..................................................................................................... 73
Tutorial 1
Procedure ...................................................................................................... 74
Conclusion..................................................................................................... 83
261 ................................................................................................... 3
PEG-4 Compliance................................................................................ 16
P4 Compliance Basics. .................................. ................................ .......... 31
3GPP/MPEG-4 Compliance ........................................................................ 42
MPEG-4 and H.264/AVC Buffer Analysis ...................... .................................. 51
1: Fidelity Analysis.. ................................ ................................ .................. 74
MTS4EA Elementary Stream Analyzer Tutorials i
Table of Contents
ii MTS4EA Elementary Stream Analyzer Tutorials
Getting Started
This set of eleven tutorials helps you learn more about operating the Tektronix
MTS4EA Elementary Stream Analyzer. Perform tutorials 1 through 11 in the
order they ar
e presented, regardless of the video standard of interest. Tutorial 10
relatesonlytoMPEG-2andinterlacedvideo.
The tutorial
s will help you answer the following questions:
How do you know that your video compression complies with the standards
If your codec doesn’t work well with other vendors’ codecs, where is the
problem — is it with your codec or theirs
Are you optimizing your Codec
Are you making the best use of available b andwidth
Which frames and movement types use the most bits and why
What changes to your codec software give the best reductions in bits used for
the least reduction in visual quality
What types of video content does your codec work poorly with and why
A descript
ion for each tutorial follows. (See Table 1.)
Table 1: Tutorial descriptions
Tutorial Name Standard Areas Covered
1 H.261 H.261
2
3
4
5
6
7
8
9
H.263 C ompliance and Motion
Vectors
MPEG-4 Compliance MPEG-4 Simple Profile Common errors; searching for areas
MPEG-4 Optimization MPEG-4 Adv. Simple Profile Common errors; HexView
MP4 Compliance Basics MP4/ Simple Profile/ L1(2) Extract and examine container files;
MP4 Optimization MP4/ Simple Profile/ L1(2)
3GPP/MPEG-4 Compliance 3GPP/MPEG-4 Simple Profile/ L1 Common errors; searching for areas
H.264/AVC Syntax Error H.264/AVC Extended Profile/ L3 Syntax error in PPS; trace analysis
MPEG-4 and H.264/AVC Buffer
Analysis
H.263 Baseline Errors and error log; motion vectors.
MPEG-4 ASP and H.264/AVC Buffer analysis in MPEG-4 and
Syntax error; compression
optimization; graph analysis
of codec optimization.
bitstream analysis; video navigator;
synchronize views; project files
level conformance error.
Using MB type overlays and
searching for areas of optimization.
for optimization
of syntax
H.264/AVC; fixing problems.
MTS4EA Elementary Stream Analyzer Tutorials 1
Getting Started
Table 1: Tutorial descriptions (cont.)
Tutorial Name Standard Areas Covered
10
11 Fidelity Analysis
MPEG-2 Compliance MPEG-2 Main Profile / Main Level Syntax errors; MPEG structure
analysis; interlace.
MPEG-4, MPEG-2, and H.264 Fidelity analysis; visual difference.
Basic Functions
To complete the tutorial procedures, you must be familiar with the following basic
functions. To perform the desired function, click the associated icon or type the
appropriate keyboard shortcut. (See Table 2.)
Table 2: B
Function Forward Backward
Play video
Stop video
Pause/step one frame Ctrl + A Ctrl + Shift + A
Fast forward/backward Ctrl + F Ctrl + Shift + F
Pause on frame
Skip to next frame
type/number/time
asic functions
Icon Keyboard shortcut Icon Keyboard shortcut
Ctrl + P Ctrl + Shift + P
Ctrl + S Ctrl + S
Ctrl + K Ctrl + Shift + K
How to Begin a Tutorial
1. After starting MTS4EA, click anywhere to remove the splash screen. If you
do noth
2. Load the desired tutorial stream. Note that the demo version of the MTS4EA
will on
ing, the splash screen will disappear after 4 seconds.
ly play the provided example video fi les.
2 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 1: H.261
Procedure
This tutorial shows non-compliance issues with the H.261 standard using temporal
references and graphical analysis.
1. To load the H.261 tutorial, click File > Example files > H.261 stream >
Conference Room. The window title changes to MTS4EA-H.261 Example
- Conference Room, and a warning message appears. (See Figure 1.)
Figure 1: Initial warning message
NOTE. The H .261 standard states that the temporal reference (TR) value is the
previous TR value + 1 + the number of skipped or non-reference pictures at the
picture clock frequency (PCF). TR is 8 bits only, 0–255, at the standard PCF of
29.97 frames per second. However, if a custom PCF is used, then TR is 10 bits: 8
LSBs are denoted as TR and 2 MSBs are ETR, but they are taken together as a
single 10-bit number.
2. View the warning message elements:
Warning - Indicates that two consecutive temporal references are zero.
Summary - Gives summary informat
Skip this Warning only in the future -electstoskipthisparticular
warning in the future (recommended).
MTS4EA Elementary Stream Analyzer Tutorials 3
ion about the stream.
Tutorial 1: H.261
Skip ALL Warnin
all other alerts in the future.
3. Select Skip th
4. Click the
5. As you view the video, notice the following: (See Figure 2.)
Movement in the video is too quick (requires PC with processing speed
of greater than or equal to 1 GHz)
Unwanted noise (visual artifacts) is visible when the man waves his arm
(starting around frame 128, continuing into frame 161, with some artifacts
remaining until frame 203)
Status bar notes that one alert is disabled
Although the video stream will play and will probably be decoded by other
H.261 decoders, the H.261 sequence was incorrectly e ncoded, showing
temporal issues.
is Warning only in the future, and then click Continue.
toolbar icon or type CTRL + P to resume playing the video.
g alerts in the future -electstoskipthisalertand
Figure 2: Visual artifacts
6. Click Overlay on the menu and select MB Types, or click the Overlay icon
on the toolbar. MB (macroblock) Types are color coded and can be
cked, resized, or switched off. (See Figure 3.)
undo
NOTE. The H.261 standard has 10 MB types. For more information on using
these, see the user manual.
4 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 1: H.261
Figure 3: MB overlay
7. Check that the video is in either Play or Pause mode.
8. Click the MB Tooltip icon
the left edge of the window, but you can undock it by pressing <CTRL> on
your keyboard while dragging the Tooltip with your mouse.
9. Move the mouse over the video. A white box will display around the MB
from which data is being read. The Tooltip shows information about that
MB. (Se
eFigure4.)
on the toolbar. The Tooltip typically docks at
Figure 4: MB types and data
MTS4EA Elementary Stream Analyzer Tutorials 5
Tutorial 1: H.261
10. Advance throug
the background wall. These block types use the most bits. (See Figure 5.)
h the video frame by frame, noting many green Intra MBs in
Figure 5: Intra MBs in the background wall and MB data
11. Stop the video sequence.
12. To analyze the MB data, select Analysis from the menu and select Video
graph enable. A dialog box will appear. (See Figure 6.)
6 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 1: H.261
Figure 6: Analysis dialog box
13. Check the Enable, Spatial bits/MB,andIntra coded frequency boxes in the
Analysis dialog box.
14. Select the output filename: h261.xls.
15. Click O
16. When play ends, the data is exported to the .xls file and MS Excel will open.
Click E
17. Click Spatial Bits per MB to view a graph of the spatial bits per MB. (See
Figur
K andthenplaythevideo.
nable macros. The screen will flash as the macros run.
e7.)
MTS4EA Elementary Stream Analyzer Tutorials 7
Tutorial 1: H.261
Figure 7: Spatial bits per MB
NOTE. Notice that many bits are used in the center (by the man), top left (too
many), and along the bottom edge (too many). These last two are errors.
18. Click the Intra Coded Frequency tabtoviewagraphoftheIntraCoded
Frequency. (See Figure 8.)
8 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 1: H.261
Conclusion
Figure 8
NOTE. Notice that there are many Intra-coded MBs at the top left of the graph.
This indicates that there is an error with Intra-coding in the encoder.
This tutorial demonstrated that the H .261 bitstream is not standard compliant and
that th
TR errors and frequency of playing. Coding inefficiencies were discovered
through graphical analysis.
: Intra coded frequency
ere were coding inefficiencies. These problems were discovered through
MTS4EA Elementary Stream Analyzer Tutorials 9
Tutorial 2: H.263 Compliance and Motion Vectors
Tutorial 2: H.
Procedure
263 Compliance and Motion Vectors
This tutorial
demonstrates the proper functioning of the motion vectors.
1. To load the H.263 tutorial, c lick File > Example files > H.263 stream >
Rally (250K). The window title changes to MTS4EA-H.263 Example Rally (250k), and a warning message appears. (See Figure 9.)
covers the standards and compliance issues in H.263 and also
Figure 9: Initial warning message
2. View the warning message elements:
Warning - Indicates that the PSUPP field is being sent and ignored.
Summary - Gives summary information about the stream.
Skip this Warning only in the future - elects to skip this particular
warning in the future (recommended).
10 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 2: H.263 Compliance and Motion Vectors
Skip ALL Warnin
all other alerts in the future.
3. Select Skip th
4. Click the
Another error message appears. (See Figure 10.)
5. View the error information provided, which indicates a more serious error that
occurs at bitstream byte address 0x0c9cfa, bit 3, after frame 326.
is Warning only in the future, and then click Continue.
toolbariconortypeCTRL + P to resume playing the video.
g alerts in the future -electstoskipthisalertand
Figure
6. Click Co
7. Note that it was an MBCPC error that resulted in the Out of Sync alert
MTS4EA Elementary Stream Analyzer Tutorials 11
10: Initial error message
ntinue. Another error message will appear. (See Figure 11.)
messag
e. This often occurs when one syntax error triggers a series of alerts.
Tutorial 2: H.263 Compliance and Motion Vectors
Figure 11: Out of sync error message
8. Select the Skip ALL Error alerts in the future check box, and then click
Continue.
9. To open the Alert Log, click the Alert Log icon
will appear. (See Figure 12.)
10. Note the active filter button in the toolbar. Because Skip ALL error alerts in
the future was selected, the alert log view is filtered and the filter button is
active. The status bar indicates that 2 3 of 24 alerts are hidden.
11. Click the Filter icon to deactivate the filter and view all alerts. (See Figure 13.)
. The Alert log window
12 MTS4EA Elementary Stream Analyzer Tutorials
Figure 12: Alert Log window, filtered
Tutorial 2: H.263 Compliance and Motion Vectors
Figure 13: Alert Log and Alert Details
12. Double-click an alert to view the alert details and then click Close.View
the columns that appear in the alert log and note the column descriptions
that follow. (See Figure 14.)
MTS4EA Elementary Stream Analyzer Tutorials 13
Tutorial 2: H.263 Compliance and Motion Vectors
Level -theseve
Error,andFatal.
ID - MTS4EA uni
Class - Syntax area where the alert occurs.
Title - Alert title.
Decode and Display - Frame numbers where the alert is decoded and
displayed (can vary).
Address - The address of the alert in the bitstream.
Details - Alert details.
rity level for the alert. Levels include Info, War ning,
que alert ID number.
Figure 14: Alert Log, unfiltered
13. Close the Alert log and return to the main page of the application.
14. Click the
visible. (See Figure 15.)
15. Note the following about the image:
The white dots are at the center of each MacroBlock.
The whit
the position in the previous frame that contains the data for the current
MacroBlock.
16. Click the color transfer icon
17. To play
motion vectors are clear and accurate.
icon to play the video again with the Motion Vectors (MVs)
e lines indicate motion vectors. The arrows for each MV point to
to change the overlay from white to black.
the video again, click the
icon or type CTRL + A. Note that the
14 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 2: H.263 Compliance and Motion Vectors
Conclusion
Figure 15
This tutorial demonstrated where there is a standards-compliance issue in the
H.263 bitstream, but also showed that other aspects of the H.263 bitstream, such
as the motion vectors, are implemented properly.
:Videoimage
MTS4EA Elementary Stream Analyzer Tutorials 15
Tutorial 3: MPEG-4 Compliance
Tutorial 3: MP
Procedure
EG-4 Compliance
This tutorial
Basic functions
Alerts for syntax errors
Video summary tooltip
MacroBlock overlay MB types
Optimization
Frequency of
1. To load the H
Streams > Space. An error message w ill appear. (See Figure 16.)
2. View the err
covers the following:
intra-coding
.263 tutorial, click File > Example files > MPEG-4 Elementary
or details:
The error occurs at bitstream byte address 0x11, bit 3, before VOP 1.
The error is present in the header, and MTS4EA does an initial check of
the file header when it loads the file.
The error indicates that method 1 quantization is in use, which is not
allowed b ecause the stream is Simple Profile.
3. Click Continue. MTS4EA loads the stream, and the window title changes to
MTS4EA-MPEG4 Example-Space.
4. Click the
error message will appear. (See Figure 16.)
5. Click Continue. A warning message will appear. (See Figure 17.)
icon or type CTRL + P to resume playing the stream. The same
16 MTS4EA Elementary Stream Analyzer Tutorials
Figure 16: Initial error message
Tutorial 3: MPEG-4 Compliance
Figure 17: Initial warning message
6. Click Goto, andthenclickHex. (See Figure 17.) The Hex view appears with
the error location highlighted. (See Figure 18.)
7. Close the Hex view and again view the initial error shown message. The error
occurs because modulo_time_base was set to 1 after a whole second elapsed
MTS4EA Elementary Stream Analyzer Tutorials 17
Tutorial 3: MPEG-4 Compliance
since the modul
should be reset, although not necessarily to zero).
8. Click the
appears again. (See Figure 17.)
9. In the alert dialog box, select Skip this Warning only in the future,and
then click Continue.
10. Complete the video and observe whether it works properly.
o_time_base was last 1 (at which time vop_time_increment
icon or type CTRL + P to resume playing the stream. An alert
Figure 18: Hex view with error location
11. From the Overlay menu, click Video summary tooltip to enable the Video
12. View the Final Video Summary Tooltip and note these field descriptions.
Summary tooltip.
(See Figure 19.)
Image size: 352 pixels high x 288 pixels wide (CIF).
Stream size: 976 kBytes.
Total frames: 175.
Total play time of the sequence: 13.920 seconds.
Total bits: 7,998,576.
Bandwidth required to transmit this: 574 kbits/second.
Frame play rate: 12.50 frames per second (Hz).
Clip is MPEG-4 Simple Profile with Resync markers & Method 1
quantification.
18 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 3: MPEG-4 Compliance
13. Observe how the
window.
sequence looks, and then close the Final Video Summary
Figure 19: Final video summary tooltip
14. To see if the codec makes the best use of the MPEG-4 standard, open the
Overlay menu, and then click MB Types (youcanalsotypeCTRL+ Y).
The MB Types key appears.
15. Move forward 3 frames. The MB types are color-coded. (See Figure 20.)
MTS4EA Elementary Stream Analyzer Tutorials 19
Tutorial 3: MPEG-4 Compliance
Figure 20
16. Move forw
17. View frames 35, 36 and 37, and observe that the MacroBlocks disappear.
18. Go back to frame 34.
19. From th
20. View fr
21. Compa
: MB Types color key
ard to frame 34. Note that there are several green (intra) coded
MacroBlocks in the static black background (intra coded MBs generally use
the most bits). (See Figure 21.)
(See Figure 22.)
e Overlay menu, click MB Statistics, and then click Bits.Notethat
the black background uses a high number of bits. (See Figure 23.)
ames 35, 36 and 37, and observe that the background uses
progressively fewer bits. (See Figure 24.)
re frame 34 with frame 37. Observe that the black background in
frame 34 is coded and uses many bits, while the black background in frame
37 is not coded, and it uses no bits.
20 MTS4EA Elementary Stream Analyzer Tutorials
Figure 21: Frame 34, color key
Tutorial 3: MPEG-4 Compliance
Figure 22: Frames 35, 36, and 37, color key
Figure 23: Frame 34
MTS4EA Elementary Stream Analyzer Tutorials 21
Tutorial 3: MPEG-4 Compliance
Figure 24: Frames 35, 36 and 37
Conclusion
This tutorial demonstrated how to:
Use and interpret the alert pop-up messages.
Additional Information
Covered
Use the Video summary tooltip and understand the information p rovided.
Use the MacroBlock overlays: MB types and motion vectors.
Use the hex
It appears that the encoder chooses MB types less than optimally by using intra
MBs for the background, which wastes many bits.
Consider whether there are software bugs, such that the encoder is too
sensitive to minor changes in the gray level.
Check the encoder part of the codec that decides when to use Intra MBs and
Inter MBs, and when to not code the MB.
Fixing this problem would save many wasted data bits.
NOTE. The MPEG-4 standard provides more data bits for intensity-gray level
than fo
level (this mimics the human visual system). However, it appears that the
sensitivity to gray in this example is too great.
r color information, so it is naturally more sensitive to changes in gray
view bitstream viewer.
22 MTS4EA Elementary Stream Analyzer Tutorials
Tutorial 4: MPEG-4 Optimization
Tutorial 4: MP
EG-4 Optimization
This tutorial
Use of the video navigator view.
Use of trace.
Common error: stuffing bits; using HexView to examine bitstream data.
Synchronizing views.
Saving a setup in project files.
This tutoria
you can perform the following tasks:
Play, stop,
Use and interpret the alert messages.
Use the Video summary tooltip and understand the provided information.
Use the MacroBlock overlays: MB types and motion vectors.
Use the MacroBlock and Summary tooltips.
covers the following:
l requires that you have completed the previous tutorials and that
step forward, and fast forward a video.
Procedure
Use the hexview bitstream viewer.
View Trace
1. To load the
Elementary streams> Window Car.Astuffing_bits error occurs at stream
address 0x9, bit 1, when the file is loaded. (See Figure 25.)
2. Check the box next to Skip this, and then click Continue when the
stuffing_bits alert appears.
files: Parse bitstream and interpret.
MPEG-4 tutorial, click File > Example files > MPEG-4
MTS4EA Elementary Stream Analyzer Tutorials 23